The present disclosure relates to a nonwoven cleaning article and methods of making. In particular, the present disclosure relates to an open and lofty nonwoven cleaning article that comprises natural fibers.
Nonwoven articles are used extensively in cleaning, abrading, finishing and polishing applications on a variety of surfaces. An example of an open, lofty, three dimensional nonwoven is described in U.S. Pat. No. 2,958,593 to Hoover et al. Such nonwoven webs comprise a plurality of synthetic fibers randomly arranged and secured together by an adhesive binder. Examples of scouring pads comprising non-woven fibrous materials are described in U.S. Pat. No. 2,327,199 (Loeffler), U.S. Pat. No. 2,375,585 (Rimer), and U.S. Pat. No. 3,175,331 (Klein). Nonwoven fibrous hand pads for domestic use and for more general abrasive applications are available, under the trademark “Scotch-Brite,” from 3M Company of St. Paul, Minn., USA, and nonwoven fibrous hand pads that provide mild scouring for skin cleansing are available, under the trademark “Buf-Puf,” also from 3M Company. Nonwoven fibrous scouring materials are also used outside the domestic environment, for example in floor pads such as those available, also under the trademark “Scotch-Brite”, from 3M Company.
A nonwoven fibrous scouring material is preferably a relatively open material (i.e. it has a comparatively high void volume, typically of at least 50%) so that it can retain debris removed from the surface that is being cleaned. Such a material can also be cleaned very easily by rinsing in water or another suitable liquid, so that it can be re-used.
Known processes for manufacturing nonwoven fibrous materials having a comparatively high void volume involve forming an open, three-dimensional nonwoven web of synthetic fibers, applying a liquid binder resin to the web, and then curing the binder resin to bond the fibers together. A preferred method of applying the binder resin is roll coating, which coats the fibers with the resin substantially continuously throughout the web. Abrasive particles can be adhered to the bonded web to enhance the abrasive characteristics of the web.
The use of a substantial amount of natural vegetable fibers in place of synthetic fibers in a conventional manufacturing process of the type described above has not been seen as an option for mass-producing nonwoven fibrous scouring materials having a comparatively high void volume because of the risk that the vegetable fibers will be crushed during the web forming process, when the liquid binder resin is applied, or both. A crushed web with a void volume of substantially less that 50% is too compact to function effectively as a scouring material. The risk of the fibers being crushed is considered to be particularly high if the binder resin is applied by roll coating. With that mind, EP-A-1 618 239 (3M Innovative Properties (Company) describes a method of making a scouring material comprising the steps of: forming a three-dimensional nonwoven web of natural fibers contacted with dry particulate material that includes fusible binder particles; exposing the web to conditions that cause the binder particles to form a flowable liquid binder; and then solidifying the liquid binder to form bonds between the fibers of the web and thereby provide a bonded web. Abrasive particles are then adhered to the pre-bonded web by at least a make-coat resin.
Although the method described in EP-A-1 618 239 is effective, it requires the use of an apparatus that is less widely available than that used to carry out the conventional type of manufacturing process referred to above. It would be advantageous to be able to continue to use the conventional type of process to produce nonwoven fibrous scouring materials comprising of natural vegetable fibers, and the present invention is based on the surprising discovery that this can be achieved through an appropriate selection of the fibers employed.